JP6845305B2 - Positioning system and lithography equipment - Google Patents

Description

Cross-reference of related applications
[001] This application claims the priority of US Patent Application No. 62 / 394,124 filed September 13, 2016, which is incorporated herein by reference in its entirety.

[002] This description relates to a positioning system and a lithographic apparatus equipped with this positioning system.

[003] A lithographic apparatus is a machine that applies a desired pattern on a substrate, usually on a target portion of the substrate. Lithographic equipment can be used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device, also called a mask or reticle, can be used to generate the circuit patterns formed on the individual layers of the IC. This pattern can be transferred to a target portion (eg, including a portion of a die, or one or more dies) on a substrate (eg, a silicon wafer). Usually, the pattern transfer is performed by imaging on a radiation-sensitive material (resist) layer provided on the substrate. Generally, a single substrate contains a network of adjacent target portions that are continuously patterned. Known lithography equipment scans a pattern in a specific direction (“scan” direction) with a so-called stepper, which irradiates each target portion by exposing the entire pattern onto the target portion at once, and a radiation beam at the same time. Includes so-called scanners that illuminate each target portion by scanning the substrate parallel or antiparallel in this direction.

[004] In order to improve the throughput of the lithographic apparatus, there is a tendency to increase the speed and acceleration of the stage holding the patterning device and the substrate, respectively. By increasing the speed and acceleration of these stages, the patterning device and the target portion on the substrate can move faster in the radiated beam, exposing more target portions per unit time.

[005] In a known lithographic apparatus, an optical system that forms a pattern on a target portion typically reduces the image to a quarter size. This means that the patterning device needs to move four times faster than the substrate. Development is underway to change the reduction ratio to a reduction ratio higher than 1/4, for example, 1/10. This means that the patterning device needs to move 10 times faster than the substrate.

[006] Increasing the velocity and acceleration of the stage increases the amount of kinetic energy stored in the stage. In the event of an emergency, such as a soft air error, the stage may move out of control and collide with parts of the lithographic device. Part of this lithographic device may need to absorb some or all of the kinetic energy of the stage.

[007] There are lithographic devices capable of absorbing kinetic energy, as disclosed in US Patent Application Publication No. 2015/098074, which is incorporated herein by reference in its entirety. This lithographic device has a stage assembly, a reaction mass, and a stage base. During normal use, the stage assembly moves along the X and Y axes and around the Z axis. When the stage assembly is moved by a constant force, an equal amount of opposite reaction force is applied to the reaction mass. In an emergency, the stage assembly is urged onto the reaction mass and the reaction mass is urged onto the stage base to generate braking force to stop the stage assembly and reaction mass.

[008] This lithographic apparatus has a disadvantage that a large force is transmitted to the entire lithographic apparatus in an emergency. The transmission of large forces can cause one or more delicate components of the lithographic apparatus to displace or vibrate.

[009] For example, it is desirable to provide a positioning system that reduces the amount of force transmitted from this positioning system in an emergency.

[010] According to one aspect, there is provided a positioning system for positioning an object, the positioning system comprising a stage, a balance mass and an actuator system. The stage is for holding an object. The actuator system is arranged to drive the stage in the first direction while driving the balance mass in a second direction opposite to the first direction. The stage is movable in the first direction in a certain range of movement. When the stage moves in the first direction and is at the end of the range of movement, the positioning system is arranged to cause the stage to collide forward with the balance mass.

[011] According to another aspect, a lithographic apparatus is provided that includes the positioning system, support structure, substrate table, and projection system described herein. The support structure is constructed to support the patterning device. The patterning device can impart a pattern to the cross section of the radiated beam to form a patterned radiated beam. The board table is constructed to hold the board. The projection system is configured to project a patterned radiation beam onto a target portion of the substrate. The stage of the positioning system includes one of the support structure and the board table. The object of the positioning system includes one of the patterning device and the substrate.

[012] Some embodiments will be described below with reference to the accompanying schematics, by way of example only. In these drawings, the same reference numerals indicate the corresponding parts.

[013] The lithography apparatus according to one embodiment is shown. [014] The positioning system according to one embodiment is shown. [015] A detailed view of the positioning system of FIG. 2 is shown. [016] A positioning system according to another embodiment is shown. [017] A positioning system according to still another embodiment is shown. [018] A positioning system according to still another embodiment is shown.

[019] FIG. 1 schematically shows a lithography apparatus according to an embodiment. The lithographic apparatus includes a lighting system IL, a support structure MT, a substrate table WT, and a projection system PS. The lighting system IL is configured to adjust the radiation beam B. The support structure MT is connected to a first positioning system PM constructed to support the patterning device MA and configured to accurately position the patterning device MA according to specific parameters. The substrate table WT is connected to a second positioning system PW constructed to hold the substrate (eg, resist coated wafer) W and configured to accurately position the substrate W according to specific parameters. The projection system PS is configured to project a pattern applied to the radiation beam B by the patterning device MA onto a target portion C (including, for example, one or more dies) of the substrate W.

[020] The lighting system IL is a refracting, reflective, magnetic, electromagnetic, electrostatic, or other type of optical component for inducing, shaping, or controlling radiation, or any of them. It can include various types of optical components such as combinations of.

[021] The lighting system IL receives the radiation beam B from the radiation source SO. For example, if the source SO is an excimer laser, the source SO and the lithographic apparatus may be separate components. In such cases, the source SO is not considered to form part of the lithography system, and the radiation beam B is directed from the source SO to the illuminator IL, eg, a suitable induction mirror and / or It is sent using a beam delivery system BD that includes a beam expander. In other cases, for example, when the radiation source SO is a mercury lamp, the radiation source SO can also be an integral part of the lithography apparatus. The radiation source SO and the lighting system IL, together with the beam delivery system BD, may be referred to as the radiation system, if desired.

The illumination system IL can include an adjuster AD that adjusts the angular intensity distribution of the radiated beam. In general, at least the outer and / or inner radial ranges (usually referred to as σ-outer and σ-inner, respectively) of the intensity distribution in the pupil plane of the illumination system IL can be adjusted. In addition, the lighting system IL can include various other components such as integrator IN and capacitor CO. By adjusting the radiation beam B using the illumination system IL, the cross section of the radiation beam B can have the desired uniformity and intensity distribution.

[023] The term "radiated beam" as used herein refers to ultraviolet (UV) (eg, having wavelengths of 365 nm, 355 nm, 248 nm, 193 nm, 157 nm, or 126 nm, or approximately these values). , And extreme ultraviolet light (EUV) (eg, having wavelengths in the range of 5-20 nm), as well as all types of electromagnetic radiation, including fine particle beams such as ion beams and electron beams.

[024] The support structure MT mounts the patterning device MA in a manner depending on the orientation of the patterning device MA, the design of the lithography apparatus, and other conditions such as whether the patterning device MA is held in a vacuum environment. Hold. The support structure MT can hold the patterning device MA using mechanical, vacuum, electrostatic or other clamping techniques. The support structure MT may be, for example, a frame or table that can be fixed or movable as needed. The support structure MT can reliably place the patterning device MA in a desired position with respect to, for example, the projection system PS.

[025] As used herein, the term "patterning device" refers to any device that can be used to pattern the cross section of a radiated beam so as to create a pattern within the target portion C of the substrate W. Should be widely interpreted. It should be noted that the pattern applied to the radiation beam B does not exactly match the desired pattern in the target portion C of the substrate W, for example, if the pattern includes a phase shift feature or a so-called assist feature. In some cases. Usually, the pattern attached to the radiation beam B corresponds to a specific functional layer in the device created in the target portion C such as an integrated circuit.

[026] The patterning device MA may be a transmissive type or a reflective type. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are known in lithography and include mask types such as binary, alternating phase shift, and attenuated phase shift, as well as various hybrid mask types. In one example of a programmable mirror array, a matrix array of small mirrors is used, and each small mirror can be individually tilted to reflect the incident radiated beam in different directions. The tilted mirror patterns the radiated beam B reflected by the mirror matrix.

[027] As used herein, the term "projection system" refers to refraction, reflection, as appropriate for the exposure radiation used, or for other factors such as the use of immersion liquid or the use of vacuum. It should be broadly interpreted to include any type of projection system, including reflection-refractive, magnetic, electromagnetic, and electrostatic optics, or any combination thereof.

[028] As shown herein, the lithographic apparatus is a transmissive type (eg, one that employs a transmissive mask). Further, the lithography apparatus may be of a reflective type (for example, one that employs the above-mentioned programmable mirror array or one that employs a reflective mask).

[029] The lithographic apparatus may be of a type having two (dual stage) or more substrate tables (and / or two or more patterning device support tables). In such a "multi-stage" machine, additional tables can be used in parallel, or while performing preliminary steps on one or more tables, another one or more tables are used for exposure. You can also do it. The additional table may be arranged to hold at least one sensor instead of holding the substrate W. The at least one sensor can be a sensor that measures the characteristics of the projection system PS, a sensor that detects the position of the marker on the patterning device MA with respect to the sensor, or any other type of sensor. The additional table may include, for example, a cleaning device for cleaning part of the projection system PS or any other part of the lithography system.

[030] Further, the lithography apparatus is a type in which at least a part of the substrate W can be covered with a liquid having a relatively high refractive index (for example, water) so as to fill the space between the projection system PS and the substrate W. It may be. Further, the immersion liquid may be added to another space in the lithography apparatus (for example, between the patterning device MA and the projection system PS). Immersion techniques are well known in the art by increasing the numerical aperture of the projection system. As used herein, the term "immersion" does not mean that a structure such as substrate W must be submerged in liquid, but simply between the projection system PS and substrate W during exposure. It means that there is a liquid.

[031] The radiated beam B is incident on the patterning device MA held on the support structure MT, and is patterned by the patterning device MA. After passing through the support structure MT, the radiated beam B passes through the projection system PS, which focuses the beam on the target portion C of the substrate W. A substrate using a second positioning system PW and a position sensor IF (eg, an interferometer device, linear encoder, or capacitive sensor) to position various target portions C, for example, in the path of radiation beam B. The table WT can be moved accurately. Similarly, the first positioning system PM and another position sensor (not explicitly shown in FIG. 1) are used to radiate the patterning device MA, for example, after mechanical removal from the mask library or during scanning. It can also be accurately positioned with respect to the path of the beam B. Usually, the movement of the support structure MT can be achieved by using the long stroke module and the short stroke module which form a part of the first positioning system PM. The long stroke module moves the support structure MT over a large range with limited accuracy (coarse motion positioning), while the short stroke module moves the support structure MT with respect to the long stroke module over a small range with high accuracy (coarse motion positioning). Fine movement positioning). Similarly, the movement of the substrate table WT can also be achieved using the long stroke module and the short stroke module that form part of the second positioning system PW. In the case of steppers (as opposed to scanners), the support structure MT may be connected or fixed only to the short stroke actuator.

[032] The patterning device MA and the substrate W may be aligned using the patterning device alignment marks M1 and M2 and the substrate alignment marks P1 and P2. In the example, the substrate alignment marks P1 and P2 occupy the dedicated target portion, but the substrate alignment marks P1 and P2 can also be placed in the space between the target portion C and the target C portion. The substrate alignment marks P1 and P2 are known as scribe line alignment marks when placed in the space between the target portion C and the target portion C. Similarly, when a plurality of dies are provided on the patterning device MA, the patterning device alignment marks M1 and M2 may be placed between the dies.

[033] The illustrated device can be used in at least one of the modes described below.

[034] In the step mode, which is the first mode, the entire pattern attached to the radiation beam B is projected onto the target portion C at once while keeping the support structure MT and the substrate table WT basically stationary. (Ie, single static exposure). The substrate table WT is then moved in the X and / or Y directions, whereby another target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged during a single static exposure.

[035] In the second mode, the scan mode, the support structure MT and the substrate table WT are scanned synchronously, while the pattern attached to the radiation beam B is projected onto the target portion C (ie, simply). Dynamic exposure). The speed and orientation of the substrate table WT with respect to the support structure MT can be determined by the (reduction) magnification and image inversion characteristics of the projection system PS. In the scan mode, the maximum size of the exposure field limits the width of the target portion C during a single dynamic exposure (non-scan direction), while the length of the scan operation limits the height of the target portion C (scan direction). ) Is decided.

[036] In the third mode, the support structure MT is basically kept stationary while the programmable patterning device MA is held, and the substrate table WT is moved or scanned while being attached to the radiation beam B. The pattern is projected onto the target portion C. In this mode, a pulse radiation source is typically employed, and a programmable patterning device MA is required after each movement of the substrate table WT or between successive radiation pulses during scanning. It will be updated accordingly. This mode of operation can be easily applied to maskless lithography utilizing a programmable patterning device such as the programmable mirror array of the type described above.

[037] The lithographic apparatus further comprises a control unit that controls the actuators and sensors described above. The control unit also has signal processing and data processing capabilities to perform the desired calculations related to the operation of the lithography equipment. In practical use, the control unit will be realized as a system of many subunits. Each subunit may handle real-time data collection, processing, and / or control of components within the lithographic apparatus. For example, one subunit may be dedicated to servo control of the second positioning system PW. Separate subunits may handle short stroke modules and long stroke modules, or different axes. Another subunit may be read-only for the position sensor IF. The overall control of the lithographic apparatus can be controlled by the central processing unit while communicating with the subunits, operators, and other equipment associated with the lithographic manufacturing process.

[038] Combinations and / or variations of the modes of use described above, or completely different modes of use may also be employed.

[039] FIG. 2 shows a positioning system 200 that may include a first positioning system PM or a second positioning system PW. The positioning system 200 is configured to position an object such as a patterning device MA or a substrate W. The positioning system 200 includes a stage 210, a balance mass 220, and an actuator system 230. The stage 210 is configured to hold an object. The actuator system 230 is arranged so as to drive the stage in the first direction while driving the balance mass 220 in the second direction opposite to the first direction. The first direction can be the + x direction. The second direction can be the −x direction. The stage 210 is movable in the first direction within a certain movement range 240. The positioning system 200 is arranged so that when the stage 210 moves in the first direction and is at the end 250 of the movement range 240, the stage 210 collides forward with the balance mass 220.

The positioning system 200 may include a base frame 260 for supporting the balance mass 220. The balance mass 220 is movable in the second direction with respect to the base frame 260. When the actuator system 230 applies a driving force for moving the stage 210 in the first direction, a reaction force is generated by this driving force. The reaction force has the same magnitude and the opposite direction to the driving force. Therefore, when the actuator system 230 moves the stage in the first direction, the balance mass 220 moves in the second direction. Due to the conservation of momentum, the ratio between the speed of the stage 210 and the speed of the balance mass 220 is equal to the reciprocal of the ratio between the mass of the stage 210 and the mass of the balance mass 220. Typically, the balance mass 220 has a significantly larger mass than the stage 210 (eg, 5 times, 10 times, or 20 times more mass). As a result, the speed of the balance mass 220 is significantly slower than that of the stage 210.

[041] Stage 210 has a first surface. When the stage 210 moves in the first direction, the first surface forms the front surface 280. The front surface 280 can be a front surface. The front surface 280 may be the surface closest to the balance mass 220 along the first direction. The balance mass 220 has a second surface 290. The stage 210 is arranged so as to collide with the second surface 290 at the front surface 280. The stage 210 that collides forward with the balance mass 220 can be regarded as the same as the stage 210 that collides with the second surface 290 of the balance mass 220 at the front surface 280.

[042] When the stage 210 moves in the first direction, the balance mass 220 moves in the second direction due to the preservation of momentum. For example, an emergency such as a software error, a malfunction of the position controller, or a position measurement error may occur. In such an emergency, the stage 210 may continue to move in the first direction until it reaches the end 250 of the movement range 240. At the end 250, the stage 210 collides with the second surface 290 at the front surface 280. FIG. 3 shows in more detail how the stage 210 collides with the second surface 290 at the front surface 280.

[043] FIG. 3 shows a stage 210 colliding with the balance mass 220. The front surface 280 has a contact area 310 in contact with the second surface 290. When the contact region 310 comes into contact with the second surface 290, the second surface 290 applies a collision force 320 to the contact region 310. The collision force 320 slows down the movement of the stage 210 in the first direction. When there is only one contact region 310 and the collision force 320 is also only one, the collision force 320 is equal to the combined collision force. In one embodiment, there are two or more contact areas 310, and therefore a plurality of collision forces. In such an embodiment, the combined impact force has the same effect as the impact force 320, since the combined impact force is a single force obtained by combining all the impact forces 320 into a single force. Affects stage 210. This effect can be the same if the stage 210 is considered rigid.

[044] When the stage 210 collides with the balance mass 220, the stage 210 decelerates in the first direction and the balance mass decelerates in the second direction due to the combined collision force. Since the stage 210 and the balance mass 220 collide with each other, the momentum of the combination of the stage 210 and the balance mass 220 is stored. As a result, the amount of combined collision force transmitted to the base frame 260 becomes small or zero. Nevertheless, some of the combined impact force may be transmitted to the base frame 260 by the connections to the stage 210 and the balance mass 220, such as wires and hoses. Since the amount of combined impact force transmitted to the base frame 260 is small, one or more delicate components connected to the base frame 260 are unaffected by the combined impact force. In this way, it is possible to prevent, for example, the optical component of the projection system PS from being displaced in the event of a collision of the stage 210 with the balance mass 220. The optical component may be mounted on an optical holder within the projection system PS. Optical components can have carefully set orientations and / or positions within the optical holder or projection system PS. If a large combined impact force is transmitted to the base frame 260, such carefully set orientation and / or position may be lost. The lithographic apparatus may have one or more other components that benefit from the limited amount of combined impact force transmitted to the base frame 260. Such one or more other components may include a positioning system and / or a supply system that supplies the immersion liquid between the projection system PS and the substrate W. The positioning system may include a scale and an encoder head that works with the scale. The scale or encoder head may be coupled to the base frame 260.

[045] The positioning system may include multiple encoder heads. The plurality of encoder heads are arranged on the encoder head frame. The encoder head frame may be connected to the base frame, for example via a metrology frame. When the stage 210 is in the first position within the range of movement 240, the first subset of encoder heads are used to determine the position of the stage 210. When the stage 210 moves to a second position within the range of movement 240, the positioning system switches to a second subset of the plurality of encoder heads. The second subset has at least one encoder head that is different from the first subset. By switching from the first subset to the second subset, stage 210 may exit the measurement range of one encoder head and enter the measurement range of another encoder head. During the switch from the first subset to the second subset, the positioning system can use both the first and second subsets to determine the position of stage 210.

[046] An intermediate frame may be provided and connected to the base frame 260. The intermediate frame may support one or more components of the lithographic apparatus such as scale, encoder head, feed system, and / or projection system PS. The intermediate frame can be dynamically separated from the base frame 260. The intermediate frame may support the encoder head on the first side of the stage 210, while the projection system PS is on the second side of the stage 210, which is opposite to the first side.

[047] The stage 210 has a first center of gravity 330 as shown in FIG. The collision force 320 can be parallel to the first direction (eg, the x direction). In one embodiment, the first center of gravity 330 and the collision force 320 are aligned parallel to the first direction. For example, the first center of gravity 330 and the collision force 320 are aligned along the x-axis as shown by the dotted line in FIG. Instead, or in addition, the first center of gravity 330 and the collision force 320 are aligned along the y-axis. When the first center of gravity 330 and the collision force 320 are aligned in parallel in the first direction, the amount of torque generated during a collision between the stage 210 and the balance mass 220 is reduced. By reducing the amount of torque, the vibration transmitted to the base frame 260 is reduced. When the stage 210 has only one contact area 310, the collision force 320 is the same as the combined collision force. When the stage 210 includes a plurality of contact regions 310, the plurality of collision forces 320 are combined to form a combined collision force. The combined impact force can be parallel to the first direction. The first center of gravity 330 and the combined collision force are aligned parallel to the first direction, eg, along the x-axis and / or along the y-axis.

[048] FIG. 4 shows an xy plan view of one embodiment. FIG. 4 shows a stage 210 that collides with the balance mass 220 in the contact area 310. In the contact area 310, the balance mass 220 applies a collision force 320 to the stage 210, causing the stage 210 to decelerate. The balance mass 220 has a second center of gravity 400. In one embodiment, the first center of gravity 330, the combined collision force, and the second center of gravity 400 are aligned, for example, in a direction parallel to the first direction. If the stage 210 has only one contact area 310, the combined impact force is the same as the impact force 320. When the stage 210 has a plurality of contact regions 310, the combined collision force is formed by a combination of collision forces 320 applied to the plurality of contact regions 310. By aligning the first center of gravity 330, the combined impact force, and the second center of gravity along the first direction, there is an advantage that when the stage 210 collides with the balance mass 220, the momentum applied to the balance mass 220 is substantially eliminated. Can be obtained. By avoiding the momentum being applied to the balance mass 220, the balance mass 220 does not tilt, for example, along the y-axis or z-axis. When the balance mass 220 is tilted, the balance mass 220 may cause vibration in the base frame 260.

[049] FIG. 5 is a xy plan view of another embodiment. The stage 210 includes an actuator system 230 for driving the stage 210 in the first direction. The actuator system 230 includes a first actuator 231 and a second actuator 232. In this embodiment, the first actuator 231 and the second actuator 232 are arranged on both sides of the stage 210. The balance mass 220 includes a plurality of balance mass portions, and in the present embodiment, the balance mass 220 includes a first balance mass portion 221 and a second balance mass portion 222. Each balance mass portion can be movable with respect to each other along a second direction. The first balance mass portion 221 and the second balance mass portion 222 may be movable with respect to each other along the second direction. The first balance mass portion 221 and the second balance mass portion 222 are movable with respect to the stage 210 along the second direction. The first balance mass portion 221 has a third center of gravity 501. The second balance mass portion 222 has a fourth center of gravity 502. Considering the stage 210 and the balance mass 220 as a dynamic system, the third center of gravity 501 and the fourth center of gravity 502 can be combined and represented as the synthetic center of gravity 500. The synthetic center of gravity 500 forms the second center of gravity 400. In the present embodiment, since the first balance mass portion 221 and the second balance mass portion 222 have the same size and mass, the synthetic center of gravity 500 is intermediate between the first balance mass portion 221 and the second balance mass portion 222. It is in.

[050] The stage 210 is provided with two contact areas 310. At the time of collision, the combined collision force 520 is formed by the first collision force 321 and the second collision force 322. The first center of gravity 330 aligns with the combined collision force 520 along the first direction. The first center of gravity 330, the combined collision force 520, and the combined center of gravity 500 forming the second center of gravity 400 are aligned along the first direction. In the embodiment of FIG. 5, the first center of gravity 330, the combined collision force 520, and the second center of gravity 400 are aligned along the x-axis. Alternatively or additionally, the first center of gravity 330, the first center of gravity, the combined impact force 520, and the second center of gravity 400 are aligned along the y-axis. The stage 210 may collide with the first balance mass portion 221 and the second balance mass portion 222 at the same time, first colliding with one of the first balance mass portion 221 and the second balance mass portion 222, and then the first. It may collide with the other of the balance mass portion 221 and the second balance mass portion 222.

[051] Each of the first actuator 231 and the second actuator 232 is arranged so as to generate a driving force in the first direction. The driving force generated by the first actuator 231 can move the first balance mass portion 221 in the second direction. The driving force generated by the second actuator 232 can move the second balance mass portion 222 in the second direction. The driving force in the first direction generated by the first actuator 231 and the driving force in the first direction generated by the second actuator 232 are combined to form a combined driving force 530 that drives the stage 210 in the first direction. The combined driving force 530 is applied to the center of force 540. The center of force 540 and the first center of gravity 330 are aligned along the first direction. In one embodiment, the center of force 540, the first center of gravity 330, and the second center of gravity 400 are aligned along the first direction. In one embodiment, the center of force 540, the first center of gravity 330, the second center of gravity 400, and the combined collision force 520 are aligned along the first direction. The center of force 540, the first center of gravity 330, the second center of gravity 400, and the combined collision force 520 are aligned along the first direction in the xy plane, the xz plane, or both the xy plane and the xz plane.

[052] The actuator system 230 may include a plurality of coils and a plurality of magnets. The plurality of coils cooperate with the plurality of magnets to generate an electromagnetic force that drives the stage 210. In one embodiment, the plurality of coils are arranged on the stage 210 or the balance mass 220 along the first direction. The plurality of magnets are arranged on the other side of the stage 210 and the vance mass 220. For example, the first actuator 231 has a plurality of coils (that is, electric coils) arranged along the x-axis. The plurality of coils can be rectified so that the stage 210 can move with respect to the balance mass 220 in a large movement range 240. Since the movement range 240 is large in this way, the stage 210 has a large space for accelerating and reaching a high speed. In an emergency, the high speed of the stage 210 may cause a violent collision. The positioning system 200 of one embodiment can absorb such a violent collision and limit the amount of force transmitted to the base frame 260.

[053] The positioning system 200 may include a collision buffer, which forms the contact area 310 and / or the second surface 290. The collision buffer may be part of stage 210, part of balance mass 220, or part of both stage 210 and balance mass 220. For example, the collision buffer comprises a flexible element and a collision member. The flexible element connects the collision member to the balance mass 220. In one embodiment, the collision member forms a second surface 290 that comes into contact with the contact area 310 in the event of a collision. Alternatively, or in addition, the flexible element connects the impact member to the stage 210. In that case, the collision member may form a contact area 310. The collision buffer comprises a combination of springs and dampers to provide a flexible element and can disperse the kinetic energy of the stage 210.

[054] Flexible elements may include springs and / or dampers. The collision buffer is arranged to limit the collision force 320 by applying the collision force 320 over the collision distance. The longer the collision distance, the smaller the collision force 320 can be. If the collision distance is long enough, the collision buffer can completely stop the movement of the stage 210 in the first direction. The collision buffer may be arranged to provide a constant collision force 320 over substantially the entire collision distance.

[055] The collision buffer may be arranged to decelerate the stage 210 with maximum collision deceleration when the stage 210 collides with the balance mass 220. For example, the flexible element may have the dimensions necessary to have the appropriate stiffness to achieve the desired value of maximum impact deceleration. The higher the rigidity, the higher the value of the maximum collision deceleration, that is, the stage 210 decelerates quickly. If the rigidity is low, the value of the maximum collision deceleration will be low, that is, the stage 210 will slowly decelerate.

[056] The actuator system 230 is arranged to accelerate the stage 210 at maximum drive acceleration. The maximum driving acceleration can be determined by the maximum value of the combined driving force 530 and the mass of the stage 210. The maximum collision deceleration and maximum drive acceleration may be substantially equal to each other. The stage 210 is designed to be subject to acceptable stress and strain during maximum drive acceleration. By setting the maximum collision deceleration substantially equal to the maximum drive acceleration, the stage 210 can receive acceptable stress and strain during collision deceleration, while the collision distance is minimized.

[057] Stage 210 may include a short stroke module and a long stroke module. The actuator system 230 is arranged to move the long stroke module relative to the balance mass 220. The long stroke module is arranged so as to move the short stroke module with respect to the long stroke module. The short stroke module is configured to hold an object. The long stroke module comprises a front surface 280. The long stroke module includes a front surface 280 with a contact area 310. The long stroke module is arranged so that it collides with the balance mass 220 when the long stroke module moves in the first direction and is at the end 250 of the movement range 240. In one embodiment, the short stroke module comprises a front surface 280. The short stroke module may be arranged so as to collide with the balance mass 220 when the short stroke module moves in the first direction and is at the end 250 of the movement range 240 with respect to the balance mass 220. In one embodiment, both the short stroke module and the long stroke module are arranged so as to collide with the balance mass 220. Alternatively, the short stroke module may be arranged so as to collide with the long stroke module.

[058] The balance mass 220 may be arranged to support the stage 210. In one embodiment, the stage 210 is supported by a base frame 260 or any other suitable frame. The balance mass 220 may be arranged to support the long stroke module and / or the short stroke module.

[059] FIG. 6 shows a top view of yet another embodiment. The balance mass 220 surrounds the stage 210 in the xy plane. The xy plane can be parallel to the surface of the substrate W. The surface of the substrate W has a plurality of target portions. Eight collision buffers are provided on the stage 210. The balance mass 220 has surfaces 690a, 690b, 690c and 690d, respectively, facing the stage 210. When the stage 210 moves in the + x direction, the surface 680a forms the front surface 280, and the balance mass 220 moves in the −x direction. When the stage 210 moves in the + x direction and collides with the balance mass 220, the surface 680a collides with the surface 690a forming the second surface 290. When the stage 210 moves in the −x direction, the surface 680b forms the front surface 280, and the balance mass 220 moves in the + x direction. When the stage 210 moves in the −x direction and collides with the balance mass 220, the surface 680b collides with the surface 690b forming the second surface 290. When the stage 210 moves in the + y direction, the surface 680c forms the front surface 280, and the balance mass 220 moves in the −y direction. When the stage 210 moves in the + y direction and collides with the balance mass 220, the surface 680c collides with the surface 690c forming the second surface 290. When the stage 210 moves in the −y direction, the surface 680d forms the front surface 280, and the balance mass 220 moves in the + y direction. When the stage 210 moves in the −y direction and collides with the balance mass 220, the surface 680d collides with the surface 690d forming the second surface 290.

[060] FIG. 6 shows two surfaces 680a located at predetermined distances from each other along the y direction. When the two surfaces 680a are placed at a predetermined distance from each other along the y direction, the collision buffer can stop the Rz rotation (rotation around the z direction) of the stage 210 when the stage 210 collides with the surface 690a. There are advantages such as. Similarly, since the two surfaces 680b are at a predetermined distance from each other along the y direction, the collision buffer can stop the Rz rotation of the stage 210 when the stage 210 collides with the surface 690b. Similarly, since the two surfaces 680c are at predetermined distances from each other along the x direction, the collision buffer can stop the Rz rotation of the stage 210 when the stage 210 collides with the surface 690c. Similarly, since the two surfaces 680d are at a predetermined distance from each other along the x direction, the collision buffer can stop the Rz rotation of the stage 210 when the stage 210 collides with the surface 690d.

[061] In the above embodiment, only a single stage 210 is illustrated. Instead of a single stage 210, a plurality of stages 210 (eg, two or three stages 210) may be arranged within the positioning system 200. The plurality of stages 210 may share one balance mass 220. The combined driving force 530 of each of the plurality of stages 210 can be applied to the balance mass 220. Due to the conservation of momentum, the movement of the balance mass 220 may change in response to the movement of the plurality of stages 210. For example, in a situation where one stage moves in the + x direction and another stage moves in the −x direction, the balance mass 220 may remain stationary. Therefore, even if the actuator system 230 is arranged to drive one of the stages 210 in the first direction while driving the balance mass in the second direction opposite to the first direction, it is balanced in all situations. It does not mean that the mass moves in the second direction.

[062] The balance mass 220 may be supported by the base frame 260 via one flexible element or multiple flexible elements. The flexible element may have flexibility along a second direction, eg, the x direction. The flexible element may have rigidity or substantial rigidity in another direction, such as the z direction. Alternatively, the flexible element has flexibility in the x, y and z directions. The balance mass may be supported by bearings such as one or more gas bearings (eg, one or more air bearings), one or more roller bearings, or one or more slide bearings.

[063] The stage 210 described in the above embodiment may be arranged so as to support an object. This object can be the patterning device MA or the substrate W. The object may be an optical component of the projection system PS, such as a mirror or lens. The stage 210 may move the optical components during the exposure of the target portion C.

Although specific references are made herein to the use of lithographic devices in IC manufacturing, the lithographic devices described herein are integrated optical systems, guidance patterns and detection patterns for magnetic domain memories. It should be understood that it may have other applications such as the manufacture of flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads and the like. Not surprising to those of skill in the art, in such other applications, the terms "wafer" or "die" used herein are all more general "boards" or "targets," respectively. It may be considered synonymous with the term "part". The substrate W described herein may be, for example, a track (usually a tool that applies a resist layer to a substrate and develops an exposed resist), a metrology tool, and / or an inspection before or after exposure. It may be processed by a tool. Where applicable, the disclosures herein may be applied to substrate processing tools such as those described above and other substrate processing tools. Further, since the substrate W may be processed a plurality of times to make, for example, a multilayer IC, the term substrate W used in the present specification may also refer to a substrate that already includes a multiprocessing layer. Good.

Although the specific embodiments of the present disclosure have been described above, it is clear that the present disclosure can be carried out in an embodiment other than the above. For example, the present disclosure is in the form of a computer program comprising a sequence of one or more machine-readable instructions representing the methods disclosed above, or a data storage medium (eg, semiconductor memory, magnetic) in which such a computer program is stored. It may be in the form of a disk or an optical disk).

[066] Although specific references have been made as described above for the use of embodiments of the invention in the context of optical lithography, the invention is, of course, used in other applications such as imprint lithography. However, it is not limited to optical lithography, if circumstances permit. In imprint lithography, the pattern created on the substrate is defined by the topography in the patterning device MA. The topography of the patterning device is stamped into a resist layer supplied to the substrate, on which the resist is cured by electromagnetic radiation, heat, pressure, or a combination thereof. After the resist is cured, the patterning device MA is moved out of the resist, leaving a pattern in the resist.

[067] The above description is intended to be an example rather than a limitation. Therefore, as will be apparent to those skilled in the art, modifications may be made to the invention described herein without departing from the appended claims.

Claims (13)

A positioning system for positioning an object,
A stage that is configured to hold the object and is movable in the first direction within a certain range of movement.
Balance mass and
A position measurement system with multiple encoder heads and
An actuator system configured to drive the stage in the first direction while driving the balance mass in a second direction opposite to the first direction.
When the stage moves in the first direction and is at the end of the range of movement, the positioning system is arranged so that the stage is forwardly collided with the balance mass.
The positioning system comprises a first subset of the plurality of encoder heads for determining the position of the stage when the stage is in the first position.
The positioning system comprises a second subset of the plurality of encoder heads for determining the position of the stage when the stage is in the second position.
The stage has a first surface that forms a front surface when moving in the first direction, and the balance mass has a second surface.
The stage is arranged so as to collide with the second surface on the front surface.
The front surface has a contact area for contacting the second surface.
The stage has a first center of gravity and
When the contact area comes into contact with the second surface, the second surface exerts a collision force on the contact area.
The first center of gravity and the combined collision force are aligned in parallel with the first direction.
The stage further comprises a short stroke module and a long stroke module.
The actuator system is arranged to move the long stroke module relative to the balance mass.
The long stroke module is arranged so as to move the short stroke module with respect to the long stroke module.
The short stroke module is configured to hold the object.
A positioning system in which the short stroke module and / or the long stroke module includes the front surface. The positioning system according to claim 1, wherein the second subset has at least one encoder head different from the first subset. During the switch from the first subset to the second subset, the positioning system uses both the first subset and the second subset to determine the position of the stage, claim 1 or. 2. The positioning system according to 2. The positioning system according to any one of claims 1 to 3, wherein the actuator system includes a plurality of coils arranged along the first direction on the stage or the balance mass. The balance mass has a second center of gravity and has a second center of gravity.
The positioning system according to any one of claims 1 to 4 , wherein the first center of gravity, the combined collision force, and the second center of gravity are aligned in parallel with the first direction. The balance mass includes a plurality of balance mass portions, and the balance mass includes a plurality of balance mass portions.
The positioning system according to claim 5 , wherein the combined center of gravity of the plurality of balance mass portions forms the second center of gravity. The actuator system is configured to provide a combined driving force at the center of the force to drive the stage in the first direction.
The positioning system according to claim 5 or 6 , wherein the center of the force, the first center of gravity, the second center of gravity, and the combined driving force are aligned in parallel with the first direction. With more collision buffers
The positioning system according to any one of claims 1 to 7 , wherein the collision buffer forms the contact area and / or the second surface. The collision buffer is arranged so as to decelerate the stage at maximum collision deceleration when the stage collides with the balance mass.
The actuator system is arranged to accelerate the stage at maximum drive acceleration.
The positioning system according to claim 8 , wherein the maximum collision deceleration and the maximum driving acceleration are substantially equal to each other. The positioning system according to any one of claims 1 to 9 , wherein the balance mass surrounds the stage. Further provided with a base frame configured to support the balance mass
The positioning system according to any one of claims 1 to 10 , wherein the balance mass is movable in the second direction with respect to the base frame. The base frame is arranged to support the balance mass via a flexible element.
The positioning system according to claim 11 , wherein the flexible element is flexible in the second direction. The positioning system according to any one of claims 1 to 12, and the positioning system.
With a support structure constructed to support a patterning device that can pattern the cross section of the radiating beam to form a patterned radiating beam.
A board table constructed to hold the board,
A projection system configured to project the patterned radiation beam onto a target portion of the substrate.
A lithographic apparatus in which the stage comprises the support structure and the object comprises the patterning device, or the stage comprises the substrate table and the object comprises the substrate.

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